1. Field of the Invention
The present invention relates to safety razors of the type having at least one blade permanently bonded in a disposable cartridge. More particularly, the present invention relates to a plurality of tandemly mounted blades permanently bonded in a disposable cartridge.
2. Description of the Prior Art
It is known to permanently bond a blade having a single edge in a disposable cartridge. For example, U.S. Pat. Nos. 2,654,148 and 3,388,831 each disclose a razor blade permanently bonded in a disposable cartridge. Typically, a safety razor has a guard surface situated downwardly and outwardly from the cutting edge of a blade and parallel to the cutting edge. The guard surface may be of the comb variety such as in U.S. Pat. No. 2,654,148, or formed by the outer surface of an elongated guard bar such as shown in U.S. Pat. No. 3,388,831. An advantage of a blade permanently bonded in a cartridge is that it is possible to optimize the shaving angle defined by the relationship between the cutting edge and the guard surface to minimize the possibility of nicks and cuts and to maximize shaving efficiency.
Tandemly mounted blades wherein the sides of the blades are parallel and the cutting edges of the upper blade is positioned upwardly and inwardly from the bottom blade are known in the art such as U.S. Pat. No. 3,262,206 and British Patent No. 772,532. Each of these patents teach bonding the tandemly mounted blades together to thus maintain the cutting edges in a predetermined relationship. The distance between the tandemly mounted blades should be dimensioned to provide efficient shaving action as determined by the density, location and coarseness of the hair. For example, British No. 772,532 discloses specific embodiments wherein this distance varies from about 0.036 inch to about 0.044 inch.